#include<iostream>
using namespace std;
long long n, f[30];
int main()
{
	cin >> n;
	f[0] = 1;
	f[1] = 1;
	f[2] = 2;
	for (int i = 3; i <= n; i++) {
		for (int j = 1; j <= i; j++) {
			f[i] += f[j - 1] * f[i - j];
		}
	}
	cout << f[n] << endl;
	return 0;
}